Star hole type solid propellant grain shaping tool

Abstract

The invention discloses a star-hole type solid propellant grain shaping tool which comprises a spline mandrel arranged at the rear end of a star-hole type solid propellant grain and a needle disc type tip arranged at the front end of the star-hole type solid propellant grain. A star hole is formed in the rear end of the star hole type solid propellant grain; a first through hole is formed in the spline mandrel in the axial direction, and the spline mandrel comprises a connecting section, a transition section, a mounting section, a conical section and an abutting section which are integrally connected from back to front; a plurality of second through holes communicated with the first through hole are formed in the front end surface of the abutting section; a plurality of first external splines are arranged on the outer wall of the mounting section at equal intervals in the circumferential direction, and a plurality of second external splines connected with the first external splines in a one-to-one correspondence mode are arranged on the outer wall of the conical section at equal intervals in the circumferential direction. According to the invention, the center position of the star hole of the propellant during turning can be ensured, so that the concentricity of the star hole and the outer diameter during turning of the propellant is ensured, the consistency of the thickness of the propellant is improved, the thickness error is effectively reduced, the reshaping quality of turning of the propellant is improved, and the risk of clamping looseness is eliminated.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid propellants, relates to a shaping tool for solid propellants, and particularly relates to a shaping tool for star-hole solid propellant grains. Background Art

[0002] Free-loading solid propellants have the characteristics of flexible structural design and free loading, and have been applied in weapon systems such as air-to-ground missiles and anti-tank missiles. Among them, star-hole propellant charges are a widely used charge structure. The star-hole structure can meet the power requirements of the engine during the missile take-off stage, and the design of the star-hole structure will directly affect the thrust performance of the engine. The traditional star-hole modified double-base propellant blank grain has a cylindrical star-hole structure, where the star-hole is a non-through hole structure and the bottom of the star-hole is a spherical surface structure. In order to meet the thrust requirements of the engine, it is necessary to turn and shape the outer diameter and the ball head of the propellant blank grain to meet the design requirements.

[0003] The traditional turning and shaping of star-hole propellant grains is to clamp the propellant grain on a lathe by a chuck and turn the outer diameter of the propellant. This chuck clamping turning and shaping of the propellant mainly has the following defects: (1) concentricity deviation: it is difficult to ensure the center position of the star-hole during the clamping process, resulting in uneven propellant wall thickness and affecting combustion stability; (2) manual operation risk: during the turning and shaping of the propellant, it is necessary to manually turn the grain for clamping, with a lot of manual intervention and great potential safety hazards; (3) tool setting error: the tool setting for the two turnings is not aligned, affecting the working performance of the propellant charge. Therefore, there is an urgent need for a shaping tool that can improve the processing accuracy and reduce manual intervention. Summary of the Invention

[0004] In order to overcome the deficiencies and defects of the prior art, the present invention provides a shaping tool for star-hole solid propellant grains to solve the technical problems of concentricity deviation, manual operation risk, and tool setting error existing in the traditional turning and shaping process of star-hole propellant grains in the prior art.

[0005] To achieve the above object, the present invention intends to adopt the following technical means:

[0006] A shaping tool for star-hole solid propellant grains includes a spline mandrel disposed at the rear end of the star-hole solid propellant grain and a needle-type center disposed at the front end of the star-hole solid propellant grain; a star-hole is opened at the rear end of the star-hole solid propellant grain.

[0007] A first through hole is axially disposed inside the spline mandrel. The spline mandrel includes a connection section, a transition section, an installation section, a tapered section, and an abutting section that are integrally connected from back to front; the installation section, the tapered section, and the abutting section are inserted into the star-hole; a plurality of second through holes communicating with the first through hole are opened on the front end face of the abutting section.

[0008] A plurality of first external splines are circumferentially and equally spaced on the outer wall of the installation section, and a plurality of second external splines corresponding to and connected to the first external splines one by one are circumferentially and equally spaced on the outer wall of the conical section.

[0009] The present invention also has the following technical features:

[0010] Specifically, the front end face of the abutting section is a convex curved surface, and the front end face of the abutting section can abut against the inner wall of the star hole.

[0011] Furthermore, the connecting section is of a conical structure, and the large-diameter end of the connecting section is coaxially connected to the transition section.

[0012] Furthermore, the first external spline can be in mating connection with an internal spline provided on the inner wall of the rear end of the star hole, and the length of the first external spline is 20 - 30 mm.

[0013] Furthermore, the aperture of the second through hole is 2 mm.

[0014] Furthermore, the needle disk type center point includes a disk body, and a plurality of center points with different lengths are spaced at the rear end face of the disk body.

[0015] Furthermore, the lengths of the plurality of center points decrease from outside to inside, so that a continuously fitted concave spherical surface structure is formed after the tops of the plurality of center points are connected.

[0016] Furthermore, a clamping section is provided on the front end face of the disk body, and an installation hole with an open front end is axially provided in the clamping section.

[0017] Furthermore, it further includes a steady rest, the steady rest includes a frame body, a first side arm and a second side arm symmetrically arranged on both sides of the upper part of the frame body, and at least two support rollers are further provided on the top of the frame body.

[0018] Compared with the prior art, the beneficial technical effects of the present invention are:

[0019] Through the structural design, especially through the spline mandrel and the needle disk type center point that can clamp the star-hole solid propellant grain from both the front and rear ends, the present invention can ensure the central position of the star hole of the propellant during turning, and further ensure the concentricity of the star hole and the outer diameter during turning of the propellant, improve the consistency of the propellant wall thickness, effectively reduce the wall thickness error, and ensure the normal operation of the engine; using the device of the present invention can realize one-time turning and shaping of the propellant grain, reduce the manual turning operation, and improve the turning and shaping quality at the same time; the present invention realizes the effective combination of vacuum adsorption and steady rest support, and eliminates the risk of clamping loosening. Description of the Drawings

[0020] Figure 1Schematic diagram of the assembly of the present invention;

[0021] Figure 2 Side view of a center rest supporting a star-hole solid propellant grain;

[0022] Figure 3 Cross-sectional view of the spline mandrel of the present invention;

[0023] Figure 4 Overall structural schematic diagram of the spline mandrel of the present invention;

[0024] Figure 5 Cross-sectional view of the needle-type center point of the present invention;

[0025] Figure 6 Schematic diagram of the center rest structure.

[0026] Each label in the figure represents:

[0027] 1 - Spline mandrel, 2 - Needle-type center point, 3 - Star-hole solid propellant grain, 4 - Center rest;

[0028] 11 - First through hole, 12 - Connection section, 13 - Transition section, 14 - Installation section, 15 - Tapered section, 16 - Abutted section;

[0029] 21 - Disk body, 22 - Center point, 23 - Clamping section; 31 - Star hole; 41 - Frame body, 42 - First side arm, 43 - Second side arm, 44 - Support roller;

[0030] 141 - First external spline; 151 - Second external spline; 161 - Second through hole; 231 - Installation hole.

[0031] The present invention will be specifically described below in conjunction with the accompanying drawings of the specification and the specific embodiments. Specific Embodiments

[0032] Complying with the above technical solutions, the following specific embodiments of the present invention are given. It should be noted that the present invention is not limited to the following specific embodiments, and any equivalent transformation made on the basis of the technical solutions of this application falls within the protection scope of the present invention. The present invention will be further described in detail below in conjunction with the embodiments.

[0033] When the present invention describes directions, the directions or positional relationships indicated by terms such as "upper", "lower", "front", "rear", "left", "right", etc. are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be construed as a limitation to the present invention.

[0034] In addition, the terms "first" and "second" are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. Unless otherwise stated, terms such as "installed", "connected", "joined", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components or the interaction relationship between two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] It should be noted that all components in the present invention, unless otherwise specified, are components known in the art.

[0036] Embodiment 1

[0037] Following the above technical solution, as Figures 1 to 6 shown, this embodiment provides a shaping tooling for a star-hole solid propellant grain, including a spline mandrel 1 arranged at the rear end of the star-hole solid propellant grain 3 and a needle plate type center point 2 arranged at the front end of the star-hole solid propellant grain 3; a star hole 31 is opened at the rear end of the star-hole solid propellant grain 3; wherein, the spline mandrel 1 and the needle plate type center point 2 are used to realize the axial and radial fixation of the star-hole solid propellant grain 3 through vacuum adsorption and profiling fit.

[0038] Specifically, a first through hole 11 is axially arranged inside the spline mandrel 1. The spline mandrel 1 includes a connection section 12, a transition section 13, an installation section 14, a tapered section 15, and an abutting section 16 that are integrally connected from the rear to the front. The installation section 14, the tapered section 15, and the abutting section 16 are inserted into the star hole 31; a plurality of second through holes 161 communicating with the first through hole 11 are opened on the front end face of the abutting section 16;

[0039] A plurality of first external splines 141 are circumferentially and equally spaced on the outer wall of the installation section 14, and a plurality of second external splines 151 corresponding to and connected with the first external splines 141 one by one are circumferentially and equally spaced on the outer wall of the tapered section 15.

[0040] Preferably, the number of the first external splines 141 and the second external splines 15 is the same as the number of star angles of the star hole 31, both being 3 - 7.

[0041] As a preferred solution of this embodiment, the front end face of the abutting section 16 is a convex curved surface, and the front end face of the abutting section 16 can abut against the inner wall of the star hole 31.

[0042] As a preferred solution of this embodiment, the connecting section 12 is a conical structure, and the large-diameter end of the connecting section 12 is coaxially connected to the transition section 13. The connecting section 12 can cooperate with the lathe chuck to achieve quick clamping.

[0043] As a preferred solution of this embodiment, the first external spline 141 can be connected in a mating manner with the internal spline provided on the inner wall at the rear end of the star hole 31, and the length of the first external spline 141 is 20 - 30 mm.

[0044] The 20 - 30 mm long first external spline 141 can be closely fitted with the 20 - 30 mm long internal spline circumferentially provided on the inner wall of the star hole 31.

[0045] Through experimental verification, when the spline length is 20 - 30 mm, the fitting accuracy between the star hole 31 and the spline mandrel 1 reaches ±0.1 mm, which can ensure that the center of the star hole 31 is concentric with the lathe spindle during turning, effectively avoiding turning deviation. When the spline length is 20 - 30 mm, it can also avoid quality problems caused by scratches due to the contact between the spline mandrel 1 and the star hole 31 when preparing the propellant grain into a finished product in the later stage.

[0046] As a preferred solution of this embodiment, the aperture of the second through hole 161 is 2 mm. With the help of the second through hole 161, during vacuum adsorption, the star-hole solid propellant grain 3 can be adsorbed and fixed to prevent it from sliding.

[0047] Specifically, the first through hole 11 can be connected to the vacuum system. The front end face of the abutting section 16 of the experience experience spline mandrel 1 is a convex curved surface, which can be closely fitted with the inner wall of the star hole 31. The vacuum adsorption through the 161 hole acts on the bottom surface of the star hole 31, thereby forming adsorption and fixation.

[0048] As a preferred solution of this embodiment, the needle-type center 2 includes a disc body 21. A plurality of center pins 22 with different lengths are arranged at intervals on the rear end face of the disc body 21, and the lengths of the center pins 22 decrease from the outside to the inside.

[0049] As a preferred solution of this embodiment, the tops of the plurality of center pins 22 with different lengths are connected to form a continuously fitted concave spherical surface structure. The concave spherical surface structure can match the spherical head structure of the star-hole solid propellant grain 31 to prevent the star-hole solid propellant grain 3 from deviating during turning.

[0050] As a preferred solution of this embodiment, a clamping section 23 is provided on the front end face of the disc body 21. The clamping section 23 is a cylindrical structure for cooperating with the tailstock center of the lathe, and an axially arranged mounting hole 231 with an open front end is provided inside the clamping section 23.

[0051] As a preferred solution of this embodiment, it further includes a steady rest 4. The steady rest 4 is used to support the star-hole solid propellant grain 3, and includes a frame body 41, a first side arm 42 and a second side arm 43 symmetrically arranged on both sides of the upper part of the frame body 41. At least two support rollers 44 are further arranged on the top of the frame body 41.

[0052] Preferably, the surface of the support rollers 44 is coated with a flexible material, and the distance between the two support rollers 44 is adjustable to adapt to star-hole solid propellant grains 31 with different diameters. The support rollers 44 of the steady rest 4 are linked with the lathe guide rail, which can further ensure the stability of the star-hole solid propellant grain during the turning process.

[0053] In this embodiment, the bottom end of the frame body 41 is connected to the lathe through a guide rail, and the lifting of the frame body 41 can be controlled by the lathe.

[0054] When the present invention is in use, it includes the following steps:

[0055] Step 1: Insert the spline mandrel 1 into the star hole 31 of the star-hole solid propellant grain 3, so that the spherical surface at the front end of the abutting section of the spline mandrel abuts against the inner spherical surface of the star hole 31 of the star-hole solid propellant grain 3;

[0056] Step 2: Fix the clamping section 23 of the needle-type center 2 on the tailstock of the lathe and cooperate with the lathe for fixation;

[0057] Step 3: Install the assembled star-hole solid propellant grain 3 and spline mandrel 1 into the lathe chuck, so that the connecting section 12 of the spline mandrel 1 cooperates with the lathe chuck, and start vacuum adsorption. During the turning process, the axial fixation of the star-hole solid propellant grain 3 can also be maintained through vacuum adsorption. Move the lathe tailstock to make the needle-type center 2 cooperate with and fix the end face of the star-hole solid propellant grain 3;

[0058] Step 4: Start turning and shaping the propellant grain, complete the turning and shaping of the outer circle of the star-hole solid propellant grain 3. After the outer circle turning is completed, control the steady rest 4 to rise to support the star-hole solid propellant grain 3, and the lathe tailstock automatically retracts to turn and shape the ball head of the star-hole solid propellant grain 3;

[0059] Step 5: After the turning and shaping is completed, manually remove the star-hole solid propellant grain 3.

[0060] Application example

[0061] In this application example, the star-hole solid propellant grain shaping tooling provided in Embodiment 1 is used to turn and shape the star-hole solid propellant grain, and after the turning and shaping, the propellant grain is measured, and the results are shown in Table 1.

[0062] Comparative example

[0063] In this comparative example, an existing device was used to turn and shape a star-hole solid propellant grain in a clamping and fixing manner. After turning and shaping, the grain was measured, and the results are shown in Table 1.

[0064]

[0065] Through the above comparison, it can be found that: through the structural design, the invention realizes the tight fit between the spline mandrel 1 and the star hole 31, ensures the concentricity between the center and the outer diameter of the star hole 31, and eliminates the concentricity deviation; through the fitting spherical surface structure formed by the center pin 22 of the needle plate type center 2, it fits and fixes with the spherical head of the hole-type solid propellant grain, avoids turning offset, and reduces the tool setting error; through the synergistic effect of the structural design and vacuum adsorption, the adsorption force is evenly distributed on the inner wall of the star hole 31, avoids the deformation of the grain caused by local stress concentration, realizes one-time turning, and reduces the risk of manual intervention.

[0066] The preferred embodiments of the present disclosure have been described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0067] In addition, it should be noted that, in the above specific embodiments, the various specific technical features described can be combined in any suitable manner without conflict. To avoid unnecessary repetition, the present disclosure will not separately describe various possible combination methods.

[0068] In addition, any combination can be made between various different embodiments of the present disclosure as long as it does not violate the idea of the present disclosure, and it should also be regarded as the content disclosed by the present disclosure.

Claims

1. A star-hole solid propellant grain shaping tool, comprising a spline core shaft (1) arranged at the rear end of the star-hole solid propellant grain (3) and a needle-disc tip (2) arranged at the front end of the star-hole solid propellant grain (3); the rear end of the star-hole solid propellant grain (3) is provided with a star hole (31); A first through hole (11) is axially arranged in the spline core shaft (1), and the spline core shaft (1) comprises a connecting section (12), a transition section (13), a mounting section (14), a tapered section (15) and an abutting section (16) which are integrally connected from back to front; the mounting section (14), the tapered section (15) and the abutting section (16) are inserted into the star hole (31), and a plurality of second through holes (161) communicating with the first through hole (11) are formed on the front end surface of the abutting section (16); A plurality of first external splines (141) are arranged at equal intervals along the circumferential direction on the outer wall of the mounting section (14), and a plurality of second external splines (151) are arranged at equal intervals along the circumferential direction on the outer wall of the tapered section (15) and are connected to the first external splines (141) in a one-to-one correspondence.

2. The star-hole type solid propellant grain shaping tool as claimed in claim 1, characterized in that: The front end surface of the abutting section (16) is a convex curved surface, and the front end surface of the abutting section (16) can abut against the inner wall of the star hole (31).

3. The star-hole type solid propellant grain shaping tool as claimed in claim 1, characterized in that: The connecting section (12) is a conical structure, and the large diameter end of the connecting section (12) is coaxially connected to the transition section (13).

4. The star-hole type solid propellant grain shaping tool as claimed in claim 1, characterized in that: The first external spline (141) can be matched and connected with the internal spline arranged on the inner wall of the rear end of the star hole (31), and the length of the first external spline (141) is 20-30 mm.

5. The star-hole type solid propellant grain shaping tool as claimed in claim 1, characterized in that: The diameter of the second through hole (161) is 2 mm.

6. The star-hole type solid propellant grain shaping tool as claimed in claim 1, characterized in that: The needle-disc type top (2) comprises a disk body (21), and a plurality of top needles (22) of different lengths are arranged at intervals on the rear end surface of the disk body (21).

7. The star-hole type solid propellant grain shaping tool as claimed in claim 6, characterized in that: The lengths of the plurality of ejector pins (22) decrease from the outside to the inside, so that a continuously fitted concave spherical structure is formed after the top ends of the plurality of ejector pins (22) are connected.

8. The star-hole solid propellant grain shaping tool as claimed in claim 6, characterized in that: A clamping section (23) is provided on the front end surface of the disc body (21), and a mounting hole (231) with an open front end is axially provided in the clamping section (23).

9. The star-hole type solid propellant grain shaping tool as claimed in claim 1, characterized in that: The invention also comprises a central frame (4), wherein the central frame (4) comprises a frame body (41), a first side arm (42) and a second side arm (43) symmetrically arranged on both sides of the upper part of the frame body (41), and at least two supporting rollers (44) are also arranged on the top of the frame body (41).

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